This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Prenatal and postnatal nutrition has been shown to be important in programming of body composition and metabolic characteristics in humans and animals. Stearoyl-CoA desaturase enzyme-1 (SCD1) is an enzyme that converts saturated fatty acids (18:0 and 16:0) to monounsaturated fatty acids (18:1 and 16:1, respectively) and has been implicated in development of obesity, diabetes, and metabolic syndrome. Nutritional programming effects on SCD1 activity have not yet been explored. In this study, we plan to study SCD1 activity in infants exposed to in utero overnutrition, infants exposed to in utero undernutrition, and compare them to infants exposed to in utero nutritional balance. We wish to establish the role of SCD1 activity in nutritional programming so that it can be studied as a target for prevention of obesity in early life. Our hypothesis is that in utero states of maternal overnutrition or undernutrition will lead to an increase in the ratio of monounsaturated to saturated fatty acids in the blood, called the desaturation index and that the increase in desaturation index will be predictive for development of adiposity in young children. An increase in the desaturation index would represent upregulation of the enzyme SCD1. Aim of this study: To compare the desaturation index in newborn infants exposed to in utero overnutrition and undernutrition, versus normal controls.